The present invention refers to a vibration dampening system to be used in a reciprocating compressor driven by a linear motor, in which the fixation of the motor-compressor assembly to the shell is generally made by springs.
In a reciprocating compressor with a linear motor (FIG. 1) the compression mechanism of the gas occurs by the axial movement of a piston inside a cylinder. Suction and discharge valves are located in the cylinder head, for controlling the admission and discharge of the gas in relation to the cylinder. The piston is driven by an actuator, which carries a magnetic component actuated by a linear motor. The piston is connected to a resonant spring and forms, jointly with the magnetic component and the spring, the resonant assembly of the compressor.
The compressor is mounted inside a shell onto an assembly of dampening springs (having a coefficient of elasticity KS), whose function is to minimize the transmission of vibration resulting from the movement of the resonant assembly.
The vibrations generated during normal operation of the compressor are produced by oscillation of the mass of the mechanical assembly of the compressor
During operation, the resonant assembly, of mass MP, is displaced in relation to the assembly formed by the cylinder and the motor (reference assembly, of mass MR) driven by the motor. By the action-reaction principle, the reference assembly will have a displacement proportional to the ratio of the masses of these two assemblies (FIG. 2). Such displacement of the reference assembly, which is seated on the dampening springs, transmits an alternate force to the shell of the compressor, causing said shell to vibrate, which is undesirable in this kind of machine generally used in the refrigeration systems of household appliances.
It is a generic objective of the present invention to provide a vibration dampening system for a reciprocating compressor with a linear motor, which allows achieving a considerable attenuation of the vibration resulting from the operation of the compressor.
This objective is achieved by a vibration dampening system for a reciprocating compressor with a linear motor of the type comprising: a shell, a motor-compressor assembly comprising a reference assembly formed by a motor and a cylinder and mounted inside the shell by dampening springs, and a resonant assembly formed by a resonant spring and a piston reciprocating inside the cylinder, said system comprising at least one first balancing means connecting the reference assembly to the shell, and at least one second balancing means connecting the resonant assembly to the shell, both balancing means actuating according to the displacement direction of the piston, said second balancing means presenting a coefficient of elasticity proportional to the coefficient of elasticity of the first balancing means, by a factor defined by the ratio of the masses of the resonant assembly and of the reference assembly, respectively.